we'll talk to a former secret service agent who served on president obama's detail. but first pete williams has more on the challenges posed by an event of this size and scope. good morning, pete. >> good morning, matt. most heavily secured event in washington. they anticipate a much smaller turnout but for the secret service the preparation is just as intense. an 11-year veteran of the secret service, dan bunchino, knows what goes into making it safe. >> we think about what you don't have to, chemical attacks, vehicle-born explosives, a fire. you have to make pennsylvania avenue nearly a quadron of washington, d.c. as secure as the white house. >> reporter: before retiring he was in the elite group assigned to product the president. he walked a few steps from barack and michelle obama in the last inauguration. >> reporter: tell me what it's like when you are walking a few steps away from a presidential limousine or president and first lady and looking at all these buildings. what's going through your mind? >> a little bit of fear. it's like riding a motorcycle. the